Peculiar motions of the gas at the centre of the barred galaxy UGC 4056

¹ Main Astronomical Observatory, National Academy of Sciences of Ukraine, 27 Akademika Zabolotnoho St., 03680 Kyiv, Ukraine
e-mail: zinchenko@mao.kiev.ua
² Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstr. 12-14, 69120 Heidelberg, Germany
³ University of Applied Sciences of Mittelhessen, Campus Friedberg, Department of Mathematics, Natural Sciences and Data Processing, Wilhelm-Leuschner-Straße 13, 61169 Friedberg, Germany
⁴ Kazan Federal University, 18 Kremlyovskaya St., 420008 Kazan, Russian Federation
⁵ Instituto de Astrofísica de Andalucía, CSIC, Apdo, 3004, 18080 Granada, Spain
⁶ The International Center of Future Science of the Jilin University, 2699 Qianjin St., 130012 Changchun City, PR China
⁷ Institut of Radio Astronomy of National Academy of Sciences of Ukraine, 4 Mystetstv Str., 61002 Kharkov, Ukraine
⁸ College of Physics, The Jilin University, 2699 Qianjin St., 130012 Changchun, PR China

Received: 12 May 2019
Accepted: 8 July 2019

Abstract

We derive the circular velocity curves of the gaseous and stellar discs of UGC 4056, a giant barred galaxy with an active galactic nucleus (AGN). We analyse UGC 4056 using the 2D spectroscopy obtained within the framework of the Mapping Nearby Galaxies at APO (MaNGA) survey. Using images and the colour index g − r from the Sloan Digital Sky Survey (SDSS), we determined the tilt of the galaxy, which allows us to conclude that the galaxy rotates clockwise with trailing spiral arms. We found that the gas motion at the central part of the UGC 4056 shows peculiar features. The rotation velocity of the gaseous disc shows a bump within around three kiloparsecs while the rotation velocity of the stellar disc falls smoothly to zero with decreasing galactocentric distance. We demonstrate that the peculiar radial velocities in the central part of the galaxy may be caused by the inflow of the gas towards the nucleus of the galaxy. The unusual motion of the gas takes place at the region with the AGN-like radiation and can be explained by the gas response to the bar potential.